I like using Merino wool for the base layer. Got a few different ones The latest I bought from Amazon https://www.amazon.co.uk/gp/product/B013VC2VPK/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
At £30.00 it's the cheapest I've found.
Good thing about Merino is that you can wear it in cool...